Southern California Earthquake 2025 Cause. With a magnitude of 7.1, the ridgecrest mainshock, as it is known, was the largest earthquake to strike southern california in 20 years, causing damage to nearby communities already impacted by the earthquake the day before. It represents the best available science for.

A magnitude 4.6 earthquake struck near malibu on friday and was felt across a wide swath of southern california. How do earthquakes get on these maps?